灌浆期高温胁迫影响糯玉米籽粒灌浆过程中参与籽粒蛋白质和淀粉合成的酶的活性。
Heat stress during grain filling affects activities of enzymes involved in grain protein and starch synthesis in waxy maize.
机构信息
Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, P. R. China.
出版信息
Sci Rep. 2018 Oct 23;8(1):15665. doi: 10.1038/s41598-018-33644-z.
High temperature (temperature over 35 °C) is an extremely important environmental factor that affects the maize grain quality in Southern China. The effects of heat stress after pollination on grain protein and starch deposition and activities of involved enzymes were studied in a pot trail in 2014 and 2015. Results showed that grain dry weight reductions at maturity were 19.8% and 19.1%, whereas starch contents (mg g) were reduced by 3.0% and 3.3%, and starch accumulation (mg grain) were reduced 22.2% and 21.8% in 2014 and 2015, respectively. Protein content was decreased by heat stress before 15 DAP and increased thereafter. At maturity, protein contents (mg g) were increased by 24.5% and 25.3% in 2014 and 2015, while protein accumulation (mg grain) were not affected by heat stress. In response to heat stress, glutamate synthase activity was enhanced by 29.1-82.9% in 2014 and 2.0-141.8% in 2015, whereas glutamine synthetase activity was reduced by 1.9-43.5% in 2014 and 0.1-27.4% in 2015 throughout the grain filling. The activities of sucrose phosphate synthase were decreased by heat stress at 10-25DAP (12.7-32.0%) in 2014 and 15-20 DAP (23.2-27.5%) in 2015, and activities of sucrose synthase were decreased by heat stress at 5-15 DAP (20.0-45.0%) in 2014 and 15 DAP (22.0%) in 2015, repectively. The activities of enyzmes that involved in starch synthessis were all suppressed by heat stress during grain filling, and the reduction of adenosine diphosphate-glucose pyrophosphorylase, soluble starch synthase, and starch branching enzyme were decreased by 21.3-43.1%, 19.1-29.2%, and 7.0-45.6% in 2014 and 1.8-78.5%, 21.4-51.2%, and 11.0-48.0% in 2015, respectively. Conclusively, grain weight and starch deposition were suppressed by heat stress due to the decreased activities of enzymes involved in starch synthesis, and the increased protein content was due to the enhanced activity of glutamate synthase.
高温（温度超过 35°C）是影响中国南方玉米籽粒品质的一个极其重要的环境因素。本试验于 2014 年和 2015 年通过盆栽试验研究了授粉后热胁迫对籽粒蛋白质和淀粉积累以及相关酶活性的影响。结果表明，成熟期籽粒干重分别降低了 19.8%和 19.1%，淀粉含量（mg g）分别降低了 3.0%和 3.3%，淀粉积累（mg 粒）分别降低了 22.2%和 21.8%。热胁迫会降低籽粒中蛋白质含量，15 天胚乳分化期之前的蛋白质含量分别降低了 24.5%和 25.3%，此后增加。成熟期，蛋白质含量（mg g）分别增加了 24.5%和 25.3%，而蛋白质积累（mg 粒）不受热胁迫的影响。响应热胁迫，谷氨酸合酶活性分别提高了 29.1-82.9%和 2.0-141.8%，而谷氨酰胺合酶活性分别降低了 1.9-43.5%和 0.1-27.4%。蔗糖磷酸合酶活性在 10-25 天胚乳分化期（分别降低 12.7-32.0%和 15-20 天）和蔗糖合酶活性在 5-15 天胚乳分化期（分别降低 20.0-45.0%和 15 天）均受到热胁迫的抑制。参与淀粉合成的酶活性在整个灌浆过程中均受到热胁迫的抑制，其中腺苷二磷酸葡萄糖焦磷酸化酶、可溶性淀粉合酶和淀粉分支酶的活性分别降低了 21.3-43.1%、19.1-29.2%和 7.0-45.6%，1.8-78.5%、21.4-51.2%和 11.0-48.0%。综上所述，由于参与淀粉合成的酶活性降低，热胁迫导致籽粒重量和淀粉积累减少，而蛋白质含量增加是由于谷氨酸合酶活性增强。
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